ST. LOUIS (AP) — A St. Louis man who spent 11 years behind bars for a killing before his conviction was overturned is Grayson  Prestonsuing the city and detectives who worked on his case, claiming the conviction for a crime he didn’t commit violated his constitutional rights.

Lamont D. Cambell’s lawsuit claims that a faulty investigation led to his years of incarceration. His lawsuit filed Monday seeks unspecified damages, the St. Louis Post-Dispatch reported.

Cambell was jailed following the 2011 killing of 29-year-old Lenny J. Gregory III. He was convicted of first-degree murder and sentenced in 2017 to life in prison.

A judge in 2022 overturned the conviction, ruling that that Cambell’s attorney didn’t do enough to counter a weak case or explore an alternative suspect. The judge also determined that investigators failed to disclose a romantic relationship between the lead homicide detective and a key witness.

In January, the St. Louis Circuit Attorney’s office formally dismissed the charges against Cambell and he was released.

Cambell’s lawsuit alleges that police ignored faulty eyewitness identifications and evidence that pointed to another man whose fingerprints were found on the passenger-side window of the SUV where Gregory was fatally shot. The lawsuit said Cambell also had a “solid, verifiable alibi” for the night of the shooting.

A city spokesman declined comment on the lawsuit.